Indexing mechanism



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INDEXING MECHANI SM Filed June 5, 1943 7 ShetS-Sheet 5 me/whom oct. 3, 1944. C, HERZOG 2,359,420

INDEXIG MECHANI SM Filed June 5, 1945 7 Sheets-Sheet 6 E 1E; El

Oct. 3, 1944. c. HERZOG INDEXING MECHANISM Filed June 5, 1945 Sme/wm cWzHeTZg/g.

Patented Oct. 3, 1944 UNITED STATES PATENT GFFICE INDEXING MECHANISM Carl Herzog, Belleville, N. J.

Application June 5, 1943, Serial No. 489,829

1,8 Claims. (Cl. 'i4-120) My invention relates to indexing mechanism.

An important object of the invention is to provide Vmeans which will eiect an intermittent turning movement of an indexing element or table, and positively hold the same against turning movement during the working period.

A further object of the invention is to provide means of the above mentioned character which may be formed from racks and pinions, which are readily available.

A further object of the invention is to provide means whereby the extent of the turning movement of the indexing element or table may be varied, during the indexing period.

A further object of the invention is to provide means whereby a rotatable element which actuates the indexing mechanism is turned at a constant speed or a constant combination of speeds throughout a portion of the tuming cycle during the working period and at an increased speed during the remainder of the turning cycle and during the indexing period.

A further object of the invention is to provide apparatus of the above mentioned character, which is automatic in operation, and positive and reliable in such operation.

Other objects and advantages of the invention will be apparent during the course of the followingA description.

In the accompanying drawings forming a part of this application and in which likenumerals are employed to designate like parts throughout the same,

Figure 1 is a perspective view of the indexing mechanism embodying my invention,

Figure 2 is a perspective view of the means which intermittently turns the indexing table, showing the reciprocatory carrier locked in the raised position, the locking rack held in the raised inactive position, and the indexing rack about to start upon its indexing movement,

Figure 3 is a similar view, showing the indexing rack at the end of its indexing movement, the reciprocatory operating member moved down one half of its own stroke, the reciprocatory carrier unlocked for downward movement, and the locking rack about to start upon its downward locking movement,

Figure 4 is a similar view, showing the reciprocatory carrier locked at the end of its down stroke, the locking rack in the lowered locking position, the operating member in the lowermost lowered and the operating member moved to one half of its up stroke to unlock the carrier, and the indexing rack shifted to the starting position while lowered,

Figure 6 is a horizontal section taken on line 6-6 of Figure 2,

Figure- 'l is a perspective view, partly diagrammatic, of variable speed gearing, and

Figure 8 is a side elevation, partly diagrammatic, of hydraulic means to shift the carrier.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of my invention, the numeral IIl designates a base, upon which is mounted a vertical housing Il. This vertical housing receives a vertical rotatable shaft I2, upon which is mounted a horizontal rotatable indexing table I3 having a horizontal gear I4 beneath it. The gear Il is rotatable with the table and serves to turn it. The table is intermittently turned, during a portion of the turning cycle of the operating element and remains stationary during the remainder of the turning cycle. The table remains stationary during the work period. The speed of the turning of the operating element must remain constant or have a constant combination of speeds during the work period but is increased during the indexing period.

Preferably formed integral with the housing I I is a vertical frame I5, including an upper horizontal guide I6 and lower horizontal guides I'I, as shown.

The numeral I8 designates a vertical reciprocatory carrier or slide, having its vertical edges slidably mounted within grooves I 9 formed in the guide I6 and grooves 2li formed in the guides Il. This reciprocatory carrier has a horizontal locking rack 2l, preferably formed integral with its upper end. This locking rack is arranged to engage and disengage the gear I 4.

The numeral 22 designates a vertical reciprocatory operating member or slide, preferably in the form of a flat plate. The operating member or slide has its longitudinal edges slidably mounted within vertical grooves 23, formed in the reciprocatory carrier I8. The reclprocatory operating member 22 is provided with a vertically inclined slot 24, provided at its ends with vertical extensions 25 and 26, extending downwardly and upwardly, respectively, as shown.

The numeral 21 designates a horizontal recip- -rocatory indexing rack, mounted for movement within a horizontal groove or guideway 28, formed upon the reciprocatory carrier I8. The

Figure 5 is a similar view, showing the carrier jl indexing rack 21 is arranged beneath and slidably engages the locking rack 2| and the indexing rack has a longitudinal groove 29, receiving a depending tongue 30, carried by the bottom of the locking rack 2|, as shown. It is thus seen that the indexing rack 21, the locking rack 2| and the reciprocatory carrier I8 are all movable vertically as a unit, while the indexing rack 21 is movable horizontally with relation to the locking rack 2|. The indexing rack 21 is movable vertically into and out of engagement with and from the gear I4 and also serves to turn this gear.

The guide I6 includes an outer horizontal arm 3 I, Figure 6, having a transverse horizontal opening 32 receiving a sliding bolt 33, which serves to lock the'reciprocatory carrier I8 in the elevated position. This bolt is movable into a notch 34 in the reciprocatory carrier I8 and is sufliciently wide to project laterally beyond this notch. 'Ihe inner end of the bolt 33 is spaced slightly from the reciprocatory operating member 22 and is adapted to be engaged by a tapered lug 35, rigidly secured to the reciprocatory operating member 22 and shifted downwardly to release the reciprocatory carrier I8, when the operating member nears the half of its down stroke. The bolt 33 is moved inwardly to lock the reciprocatory carrier I8 with the guide I6, when the operating member 2 2 nears the end of its up stroke, by a tapered finger 35', rigidly secured to an arm 36, in turn rigidly secured to the reciprocatory operating member 22. The numeral 31 designates a companion sliding bolt mounted in a transverse opening 38, formed in the horizontal arm 3|. This companion bolt is adapted to move into a notch 39, formed in the reciprocatory carrier I8 and the bolt 31 projects laterally beyond the notch 39 and into the path of travel of a tapered lug 40, rigidly secured to the reciprocatory operating member 22, and serving to withdraw the bolt 31 from the notch 39 when the operating member 22 nears the half of its up stroke. The bolt 31 is moved into the notch by a tapered finger 4|, carried by an arm 42, rigidly secured to the reciprocatory operating member 22, when such operating member nears the end of its down stroke. l

'I'he indexing rack 21 has a' pin 43, rigidly secured thereto, carrying a roller 44, operating within the inclined slot 24. The extent of relative horizontal movement of the indexing rack depends upon the horizontal dimension of the inclined slot 24, 'and hence by varying the horizontal dimension of the slot 24, the throw of the indexing rack may be varied. Thus the throw of the indexing rack may be varied by changing the inclination of the slot 24. This may be accomplished by providing a number of operating members 22 having inclined slots 24 of different inclinations, and using a selected operating member 22. The inclined slot may be formed in a separate plate or insert detachably secured to the operating member, and different inserts having inclined slots of varying inclinations may be used with one operating member. It is thus seen that the means which eifects the indexing movement of the indexing rack may be varied or adjusted to cause the indexing rack to move for different distances.

Pivotally connected with the reciprocatory operating member 22, by means of a pin 45, is a pitman 46 pivotally connected at 41, with a,

disk 48. Variable speed gearing is provided to drive the disk 48 and this gearing is mounted Within a gear casing or box 49. The gearing is preferably identical with that shown and described in my patent for Variable speed gearing, No, 2,338,514, dated January 4, 1944. This gearing includes a small gear 49 and an outer annular clutch element 50. The disk 48, gear 49 and clutch element 50 are connected to turn as a unit upon a horizontal shaft 5| by means of pins 52. A large gear 53 is rigidly mounted upon the shaft 5| and is connected with an inner clutch element 54, by means of pins 55, so that the gear 53 and clutch element 54 turn as a unit. The clutch element 54 extends into the annular clutch element 50 and rollers 56 are arranged between the clutch elements. An annular carrier 51 is mounted upon the outer clutch element 50 and an axially extending rotatable shaft 58 is mounted upon the carrier. This shaft has a small gear 59 rigidly secured to one end thereof, engaging the large gear 53 and a large gear 6|! is rigidly mounted upon the opposite end of the shaft 58 and engages the small gear 49. The carrier 51 is provided in its periphery with a tapered annular groove 6I, receiving a brake element 62, carried by a pivoted lever 63, forced downwardly by a spring 64. The lever 63 carries a wheel 65, engaging a cam 66, preferably detachably mounted upon the disk 48. The cam 66 may extend for three-fourths of the circumference of the disk 48. The shaft 6| is driven in the direction of the arrow by a Worm Wheel 61, rigidly mounted thereon, receiving rotation from a worm 68, driven by a constant speed electric motor or the like.

While the wheel 65 is traveling upon the cam 66, the carrier 51 is free to turn with the clutch element 50, and all parts of the gearing turn as a unit, and the disk 48 is driven in the direction of the shaft 5I and at the constant speed of the shaft 5| This continues for three-fourths of the turning cycle of the saft 5|. During this portion of the turning cycle, the indexing table I3 is at rest, and hence the turning movement of the shaft 5| and the,disk 48 must be constant, or have a constant combination of speeds as the Working period of the indexing disk cannot be varied, for aselected working period. At the end of the three-fourths of the turning cycle, the roller 65 passes from the cam 66 and the brake element 62 engages the carrier 51 and holds it against turning movement. The shaft 5| now turns gear 53, turning gear 59 at an increased speed, and gear 58 turns gear 60, which turns gear 48 at an increased speed, and hence disk 48 is turned at an increased speed during the remainder of the turning cycle, which is the indexing period. It is thus apparent that the speed at which the indexing table is turned during the indexing period is increased, while the period at which the table is stationary, which is the working period, is not varied. Hence a great deal o1' time is saved by increasing the turning movement of the disk 48 and table I3, during the indexing period.

The operation of the indexing mechanism is as follows:

When the pin 41 has reached the uppermost position, Figure 2, and is about to start downwardly for the first substantially which is the indexing portion of the turning cycle of the disk 48, the pitman 46 has raised the reciprocatory carrier I8 to the uppermost position and the bolt 33 now locks the carrier to the stationary guide I6 in this uppermost position. The locking rack 2| is now above the gear I4 and free from engagement therewith. As the disk 48 turns for its rst upper 90, Figure 3, the pin 41 travels downwardly carrying pitman 48 with it and the reciprocatory operating member 22 is moved downwardly with relation to the then stationary carrier I8. The stationary carrier is locked against downward movement until the operating member 22 completes one half of its down stroke. Atthis time, while the pin 41 is traveling from the upper position in Figure 2 to the intermediate lower position of Figure 3, the indexing rack 21 is held by the carrier I8 against vertical movement with relation to the carrier and engages the gear I4. As the reciprocatory member moves downwardly from the position in Figure 2 to the position in Figure 3, the roller 44 leaves the vertical extension 25 and enters the inclined slot 24 and this roller is shifted laterally to the right by this inclined slot, until the ,vertical extension 26 is reached. The roller 44 carries the indexing rack 21 with it and this rack engaging the gear I4, turns the gear for substantially 10 to 15 for eiecting the indexing of the ber 22 reaches one half of its down stroke, the 5 lug 35 moves the bolt 33 outwardly so that it releases the reciprocatory carrier for downward vertical movement. The carrier I 8 and operating member 22 are now both capable of moving downwardly as a unit. As the disk 48 turns downwardly for the second 90, from the positionpf Figure 3 to the position of Figure 4, the carrier I8 and operating member 22 move down to the lowermost position. This downward movement of the carrier I8 lowers the locking rack 2l into locking engagement with the gear I4. When the carrier I8 moves down to the end of its down stroke, the notch 39 is brought into alignment with the bolt 31, and the finger 4I moves the bolt 31 into thenotch 39 and locks the carrier I8 to the guide I6 against upward movement, Figure 4. f

The disk 48 now turns upwardly for the first 90 from the position in Figure 4 to the position in Figure 5, and the operating member moves upwardly with relation to the carrier I8. The indexing rack 21 is now arranged beneath and out of engagement with the gear I4. The upward movement of the operating member, Figures 4 and 5, causes the roller 44 within the inclined slot 24 to be shifted to the left whereby the indexing rack 21 is shifted to the left or starting position, Figure 5. 'I'he operating member 22 has now moved up to substantially one-half of its up stroke, and at thistime the tapered lug 4u engages the bolt 31 and shifts it outwardly to release the carrier from the stationary guide I2. The carrier I8 and operating member 22 are now free to move upwardly ,as a unit, which occurs when the disk 48 turns for the second upper 90, from the position shown in Figure 5 to the position shown in Figure 2. During the turning movement of the disk from the position of Figure 5 to the position of Figure 2, the carrier I8 and operating member 22 are both elevated and the locking rack 2I is moved above the gear I4 to disengage it while the indexing rack 21 is elevated to engage with the gear I4. When the carrier I8 reaches the end of its up stroke, notch 34 is in alignment with the bolt 33, and the finger 35' engages the bolt 33 and moves it into the notch 34, thereby locking the carrier I8 in the elevated position with the stationary guide I8. The parts thus assume the position shown in Figure 2 and the cycle of operation is repeated.

Attention is called to the fact that the locking rack 2I and indexing rack 21 are so arranged with respect to the gear I4 that the locking rack engages the teeth of the gear I4 before the indexing rack 21 disengages it. The indexing rack 21 has locking engagement with the gear I4 at the end of the indexing movement of the indexing rack to positively hold the gear I4 against overrunning movement. The operating member 22 reciprocates the carrier I8 and moves the indexing rack 21 with relation to the carrier. The opeating member 22 yalso positively limits the movement of the indexing rack 21 at the end of its indexing movement. The carrier I8 moves axially of the gear I4.

While it is preferred to use variable speed gear,- ing for reciprocating theoperating member 22, yet the invention is not necessarily restricted to this arrangement, as hydraulic means may be employed for this purpose. This hydraulic means is shown in Figure 8, wherein a vertical cylinder 69 is provided, receiving a plunger 10, connected with the vertical rod 1I, in turn connected with the reciprocatory operating member 22. The numeral 12 designates valve mechanism to alternately supply liquid under pressure to one end of the cylinder 69 and to exhaust it from the opposite end. This valve mechanism is connected With pipes 15 and 18, which lead into a tank 11 holding a liquid, such as oil. The numeral 18 designates a pump connected with the pipe 15 and driven by a motor 19. The valve mechanism 12 includes a part 80 arranged to be engaged by cams 8l and 82. When the operating member 22 reaches the uppermost position, Figure 8, the cam 82 engages part 80 and the valve mechanism is actuated so that the liquid is supplied through pipe 15 and pipe 13 to the top of the cylinder 69, while fluid is exhausted from the lower end of the cylinder 69 through pipe 14 and pipe 16 back t0 the tank 11. When the piston 10I reaches the endl of its down stroke, cam 8| trips part 80 and the liquid then passes through pipe 15 and pipe 14 into the bottom of the cylinder 69, While liquid is exhausted from the top of the cylinder 69 through pipe 13 and pipe 16 back to the tank 11. The piston 18 is then elevated and the cycle of operation is repeated.

It is to be understood that the forms of my invention herewith shown and described are to be taken as preferred examples of the same, and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims,

Having thus described my invention, what I claim is:

l. In indexing mechanism, means to be indexed having gear teeth, a. reciprocatory carrier, a locking member mounted upon the carrier and movable into and out of engagement with and from the gear teeth. an indexing rack mounted upon the carrier to be moved thereby into and out of engagement with and from the gear teeth, said indexing rack having an indexing movement with relation to the carrier, and means to reciprocate the -carrier and to effect the indexing movement of the indexing rack.

2. In indexing mechanism, means to be indexed having gear teeth. a reciprocatory carrier, a locking member mounted upon the reciprocatory carrier to be moved thereby into and out of engagement with and from the gear teeth, an indexing rack mounted upon the carrier to move therewith during its reciprocatory movement to engage and disengage the gear teeth, the indexing rack also having a reciprocatory movement with relation to the carrier which is transversely of the reciprocatory movement of the carrier, and means including a reciprocatory operating member mounted upon the carrier for movement with relation thereto to move the carrier and effect the indexing movement of the indexing rack.

3. In indexing mechanism, means to be indexed having gear teeth, a reciprocatory carrier, a locking member mounted upon the reciprocatory carrier to be moved thereby for engaging and disengaging the gear teeth, an indexing rack mounted upon the carrier to be reciprocated thereby for engaging and disengaging the gear teeth, said indexing rack also having an indexing movement transversely of the reciprocatory movement of the carrier, an operating member mounted upon the carrier and having a reciprocatory movement with relation to the carrier, said'operating member having an inclined part, an element secured to the indexing rack and engaging said inclined part, means'to reciprocate the operating member, and releasable means to hold the carrier against reciprocatory movement.

4. In indexing mechanism, means to be indexed having gear teeth, a reciprocatory carrier, a locking member mounted upon the reciprocatory carrier to be moved thereby for engaging and disengaging the gear teeth, an indexing rack mounted upon the carrier to be moved thereby for engaging and disengaging the gear teeth, said indexing rack also having an indexing movement with relation to the carrier, an operating member mounted upon the carrier and having a reciprocatory movement with relation to the carrier, said operating member having an inclined slot, an element secured to the indexing rack and arranged within the inclined slot, means operated by the operating member to lock the carrier against movement when the carrier and operating member are shifted to the ends of their strokes in one direction, means operated by the operating member when it moves in an opposite direction with relation to the carrier to release the locking means, means operated by the operating member to lock the carrier against movement when the Carrier and operating member move to the ends of their strokes in an opposite direction, means operated by the movement of the operating member with relation to the carrier in an opposite direction to its last named movement to release the last named locking means, and means to reciprocate the operating member.

5. In indexing mechanism, means to be indexed having gear teeth, a reciprocatory carrier, a locking member mounted upon the reciprocatory car. rier to be moved thereby for engaging and disengaging the gear teeth, an indexing rack mounted upon the carrier to be moved thereby for engaging and disengaging the gear teeth, said indexing rack also having an indexing movement with relation to the carrier, an operating member mounted upon the carrier and having a reciprocatory movement with relation to the carrier, said operating member having an inclined device, an element secured to the indexing rack and engaging the inclined device, means to lock the carrier against movement when the carrier and operating member are shifted to the ends of their strokes in one direction, means to release the locking means when the operating member is moved in an opposite direction for a part of its stroke with relation to the carrier, means to lock the carrier against movement when the carrier and operating member move to the ends of their strokes in an opposite direction, means to release the last named locking means when the operating member moves in an opposite direction to its last named movement with relation to the carrier, and means to reciprocate the operating member.

6. In indexing mechanism, means to be indexed having gear teeth, a reciprocatory carrier, stationary guide means for the carrier, a locking rack mounted upon the carrier, an indexing rack mounted upon the carrier and having an indexing movement with relation to the carrier, areciprocatory operating member mounted upon the carrier and movable with relation to the carrier and having an inclined guide device, an element mounted upon the indexing rack and engaging the inclined guide device, a bolt mounted upon the stationary guide means, means mounted upon the operating member to move the bolt into locking engagement with the carrier when the operating member is moved in one direction with relation to the carrier, means mounted upon the operating member to shift the bolt out of locking engagement with the carrier when the operating member is moved in an opposite direction with relation to the carrier, a second bolt, means mounted upon the operating member to move the second named bolt into locking engagement with the carrier when the operating member is moved in an opposite direction to which it was moved to bring the iirst named bolt into locking engagement with the operating member, means mounted upon the operating member to move the second named bolt out of locking engagement with the carrier when the operating member is moved in a direction opposite to its last named movement, and means to reciprocate the operating member.

'7. In indexing mechanism, indexing means, a

reciprocatory carrier, a locking element mounted upon the carrier and movable thereby into and out of holding engagement with and from the indexing means, an indexing element mounted upon the carrier to be moved thereby into and out of engagement with and from the indexing means, said indexing element having an indexing movement with relation to the carrier while the indexing element has driving engagement with the indexing means, and means to reciprocate the carrier and to eiect the indexing movement of the indexing element with relation to the carrier.

8. In indexing mechanism, indexing means, a movable carrier, a locking element mounted upon the carrier and moved by the carrier into engagement with the indexing means, an indexing element mounted upon the carrier and movable into engagement with the indexing means, said indexing element having an indexing movement with relation to the carrier while the indexing element has driving engagement with the indexing means, means to move the carrier, and means to effect the indexing movement of the indexing element with relation to the carrier.

9. In indexing mechanism, means to be indexed, a reciprocatory carrier, an operating member mounted upon the carrier and having a reciprocatory movement with relation to the carrier, said operating member having an inclined part, an element engaging the inclined part to be moved thereby, means operated by the operating member to lock the carrier against movement when the carrier and operating member move kto the carrier to release the locking means, means Aoperated by the operating member to lock the l reciprocatory carrier, a locking element mollted upon the reciprocatory carrier and movable thereby into and out of holding engagement with and from the indexing means, an indexing element mounted upon the reciprocatoryv carrier for movement with the carrier into and out of engagement with and from'the indexing means, said indexing element having a reciprocatory movement with relation to the carrier which is transversely of the reciprocatory rmovement of the carrier, said indexing element having its indexing movement with relation to the carrier while the indexing element 'has driving engagement with the indexing means, and means to recipro- `cate the carrier and to effect the reciprocatory indexing movement of the indexing element with relation to the carrier. l

11. In indexing mechanism, indexing means, a reciprocatory carrier: alocking element mounted upon the regiprocatory carrier and movable thereby into andut of holding engagement with and from the indexing means, an indexing element mounted uporsthe reciprocatory carrier for movement with the carrier into and out of engagement with ard from the indexing means, said indexing element having a reciprocatory movement with relation to the carrier while the indexing element has` driving engagement with the indexing meansfmeans to reciprocate the carrier, and means to eieot the reciprocatory indexing movement of the indexing element with relation to the carrier including an inclined part movable with relation vto the indexing ,element and a part secured to the indexing element and engaging the inclined part.

12. 'I'he combination with a means to be advanced, of a reciprocatory carrier associated with the means, an advancing element mounted upon the carrier to be moved thereby into and out of engagement with the means, the advancing ele-- ment .having a reciprocatory movement with relation to the carrier while the advancing element is engaging the means, a reciprocatory operating member mounted upon the reciprocatory carrier, means to reciprocate the carrier and operating member as a unit and to reciprocate the operating member with relation to the carrier, and means operated by the movement of the operating member with relation to the carrier to the indexing means, an operating member having 15 an inclined part, a bart connected with the indexing element and engaging the inclined part, means to reciprocate th` carrier and operating member as a unit and to reciprocate the operating member with relation to the carrier.

14. In indexing mechanism, means to be indexed including a movable member, said member having a stationary work period after the indexin g period, a device to engage the member and upon its indexing movement to advance the member a step and having lockingY engagement with the member at the end of such step to positively hold the member against overrunning movement, means to intermittently move the device upon its indexing movement and positively limiting the movement of the device in the same direction when the end of the indexing movement of the device is reached, a, rotary element connected with the intermittent means to ,drive th same, and variable speed mechanism connected with the rotary element to turn the rotary element at a constant speed'during a portion of its cycle of turning movement and during the stationary work period of the movable member and to turn the rotary element at an increased total speed during the remainder of its cycle of turning movement and during the indexing period of the movable member.

15. In indexing mechanism, means to be indexed including a movable member, a device to advance theA member a step upon the indexing movement of the device, said device having a positive connection lwith the member at the end of the step movement of the member to hold the member against overrunning movement, means to intermittently move the device upon its indexing movement and positively limiting the movement of the device in the same direction when the end of the indexing movement of the device is reached, a rotary element connected With the intermittent means to drive the same, and variable speed mechanism connected With the rotary elementto turn the rotary element at a constant speed during the major portion of its cycle of turning movement and at an increased total speed during the minor remaining portion of its cycle of turning movement.

16. In indexing mechanism, means to be indexed having teeth, a reciprocatory carrier, a locking member mounted upon the carrier, an indexing member mounted upon the carrier to move with relation'to the carrier, the locking member and indexing member being moved by the carrier into and out of engagement with the teeth,

said members being so arranged that the locking member engages thev teeth before the indexing member disengages the teeth, means including an operating member to reciprocate the carrier and to move the indexing member with relation to the carrier, the last named means positively limiting the movement of the indexing member at the end of its indexing movement, said indexing member having locking engagement with the teeth at the end of the indexing movement of the indexing member to positively hold the means to be indexed against overrunning movement, a rotary element turning about .a i'lxedpoint, and means driven by the rotary element to reciprocate the operating member.

17. In indexing mechanism, a gear, a carrier rer moving the rack into and out of engagement with and from the gear, the indexing rack having locking engagement with the gearv when the indexing rack is shifted to the end of its indexing movement, and means to reciprocate the carrier and to move the indexing rack with relation to the carrier and to positively limit the movement of the indexing rack when it reaches the end of its indexing movement.

CARL HERZOG. 

